1. Technical Field
The present technology pertains generally to implantable medical devices and methods and more particularly to implantable electrostimulator and sensor devices for monitoring and controlling intestinal peristalsis as a treatment for gastrointestinal disorders.
2. Background
The gastrointestinal system is a complex and essential system of the human body. Consumed food is directed through the stomach and intestines of the system through peristaltic movements. Peristalsis is achieved by a combination of neurological, hormonal, mechanical and chemical mechanisms. The frequency of propagating contractions through the gastrointestinal system is different for the different parts of the system. For example, the contraction propagation frequency in the stomach is approximately three cycles/minute were the small intestines is typically about nine cycles/minute. The timing of the contractions in the intestines is believed to be controlled by sympathetic and parasympathetic neural control circuits that generate the peristaltic waves in the system.
Various diseases, disorders, surgeries, spinal injuries or other trauma can affect the peristaltic activity of the gastrointestinal tract causing the digestive processes to malfunction. Loss of effective peristaltic activity in the gastrointestinal tract can lead to a number of significant clinical conditions. Reduced function or a complete loss of peristaltic function can result in a failure to move the intestinal contents through the digestive tract and material is retained in the intestines. For example, conditions such as paralytic ileus are characterized by distensions of the small intestine from compactions created by segments of intestine with inadequate or non-existent peristaltic activity.
Conversely, over active or excessive peristaltic activity in the whole system or segments of the system can result in the movement of material through the gastrointestinal tract to quickly so that there is not enough time for proper digestion and assimilation and conditions such as colitis. Irregular contraction propagation frequencies or activity over some segments of the digestive tract can influence the peristalsis of other segments.
Some of the conditions of dysfunctional peristalsis can be treated with a variety of medications. However, many of the medications have significant side effects or may be ineffective in treating the cause of the condition only the symptoms. Another approach to treating the irregular or non-functional peristaltic conditions is through electrical stimulation of the nerves or muscles at locations along the intestinal tract to control and regulate the peristaltic activity.
Many different ways of stimulating gastrointestinal function through electrical stimulation have been explored. Electrodes have been placed at various locations in the interior of the gastrointestinal tract such as implantation in the stomach wall or intestinal walls. However, electrodes currently used for electrical stimulation of gastrointestinal tissues are rigid and large in size in order to distribute the energy of the pulse over a large surface area to avoid tissue damage. Large rigid electrodes are susceptible to fatigue failures and separation due to the mechanical stresses created by the peristaltic contractions.
Accordingly, there is a need for gastrointestinal stimulation devices with implantable electrodes that are flexible and durable that will not have fatigue failures or electrode displacement with repeated and significant movements upon stimulation of the targeted tissues.